In order to design the building foundation for a large multifamily housing compl

Question

In order to design the building foundation for a large multifamily housing complex, a geotechnical testing company will be hired to determine the underlying soil porosity.

Based on a preliminary assessment of the soil type, the standard deviation of porosity is estimated to be 0.13.

The foundation engineer has stated that in order for her to proceed with the design, she must have the soil porosity +/- 0.06 with 95% confidence.

How many samples should you budget for in order to meet these constraints?

This table may help...

Explanation / Answer

Compute Sample Size

n = (Z a/2 * S.D / ME ) ^2

Z/2 at 0.05% LOS is = 1.96 ( From Standard Normal Table )

Standard Deviation ( S.D) = 0.13

ME =0.06

n = ( 1.96*0.13/0.06) ^2

= (0.255/0.06 ) ^2

= 18.034 ~ 19

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.